Hey guys I have a 88 Fbird with a 305 in it. Very slow.
I have been looking to do an engine swap. I found a 77 grand prix with a 400 in it. I was told that is a 400 big block. It runs very strong and will roast the tires on the big ol grand prix. I do not know if the mounts will line up or what. Is there a big block swap kit for the f-body I am in serious need of help. Any help will be very much appreciated. Thank You

 

I bet ya money it's a 400SBC...Not a big block

It should fit, how much are they asking and how many miles are on it?

Ask how many rebuilds it has had also.

Should fit and make a awesome motor for a 3rd gen.

You shouldn't have to switch out the mounts.

If you do someone will chime in, but I don't think you have to.

-Frank

 

Pontiac was still using their own engines back then. Techniclly there is no big block/small block difference with Pontiacs, they all have the same external dimensions. Except for the oddball 301.

I read an article in a mag where a racer installed a 455 Pontiac in a third gen, but I'm sure it takes some talent and custom work. And performance parts for a Pontiac are $$$$.

If it's a 400 SBC, good deal. You could even make it work if it's a BBC, there are parts out there for the BBC install.

 

Thanks guys, the guy will send me pics of it. It is in a 77 grand prix which i guess has 90k miles on the odometer and it is pretty nice shape. He wants 400 for the whole car. He said that it will roast both tires any time. I hope it will fit in my firebird.

My other option is a chev 400 small block with some nice pistons and aluminum heads. My machine shop guy has it but I think he will want a pretty penny for it.

 

stick with a small block, the BBC install is a nightmare and requires lots of fabricating from what i've seen.

it's been done plenty of times, but is it really worht it?

when you can get a decent 400hp sbc to slip right in for a couple grand...why spend the extra $$, time and aggrevation

 

Hey man I guess you were right the exaust ports on the head are like this 0 00 0 which i guess is the SBC heads so it is a SBC i guess. He will send me pics. I guess it is all original with 90k miles on it the dash no rebuilds. $400 takes the whole car. it has a turbo 400 in it I think. i can just drop them both right in. Who knows. I am surely going to get it cause it is a running driveable car. Use it for a while get my money out of it then rip out the engine and get some more money for scrapping it. He he

 

Same exhaust port configuration as a Pontiac. I will bet you money that it isn't a small block Chevy. Count the number of Valve cover screws. Is there an open valley under the intake manifold. Many other differences.

Martin

 

Hey guys I got a pic of the engine I think it has 4 valve cover bolts and no passage under the intake as the last guy was saying.

It looks like a small I do not know I am trying to post the pic but I have no place to host it my server is not online now. Soon will be

The valve covers have two bolts on the inner side and two on the outer side with little 3 inch size clips pushing on the valve cover.

 

Pontiac engines are one of the "not as popular so you pay more" motors.
And trying to do a swap into a 3rd Gen won't be easy. The 400 is much wider, I'm not sure it will fit between the Strut Towers??

I tried to put one in an '81 Cutlass "G" body, I had to do some custom welding, alignment etc,,,"Man What a Nightmare!"..
Then I got a 403 Olds cheap, and ripped it back out and put the 403 in, WOW MUCH BETTER...
There are more, cheaper, performance parts for 350's and they can run with almost any 400, when modded right...And you won't have to rengineer the whole engine compartment...My $.02..Don't Do It...